Software :: Bash Command History Log / How To Write It Continuous?

I've been looking for how to set this up in bash with no luck so far. I can change what file the history log is written to, and how much history is saved. But it only writes the saved part when bash exits. Instead, I'd like to have bash write that file continuously as each command is entered (and maybe also do an fsync(2) to flush it to disk). That way I can see the command I crashed the box with Anyone know the magical incantation for that?

But there appears to be nothing that I can find there, in the man page, or other searches, that suggest it even can do continuous.